What type of weather conditions can particularly affect urban air operations?

The correct choice highlights that fog, heavy rain, strong winds, and thunderstorms represent significant weather conditions that can adversely affect urban air operations. These conditions can lead to reduced visibility, making navigation and takeoff or landing difficult. Heavy rain may create hazards such as water accumulation on runways or landing areas, while strong winds can impact stability during flight, particularly during takeoff and landing phases.

Thunderstorms are particularly dangerous due to the potential for severe turbulence, lightning, and sudden changes in wind direction (wind shear), all of which can jeopardize flight safety. Urban air operations often occur in densely populated areas where these weather phenomena can have immediate and severe implications for both the aircraft and the surrounding environment, thus making it crucial for operators to be aware of these specific weather conditions.